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This story was printed from CdrInfo.com,
located at http://www.cdrinfo.com.
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Sony has developed a new series of back-illuminated
CMOS image sensosr for mobile devices, promising to
offer enhanced image quality and superior
functionalities at a more compact size.

Conventional CMOS image sensors mount the pixel
section and analog logic circuit on top of the same
chip, which require numerous constraints when wishing
to mount the large-scale circuits such as measures to
counter the circuit scale and chip size, measures to
suppress noise caused by the layout of the pixel and
circuit sections, and optimizing the characteristics
of pixels and circuit transistors.

Sony has established a structure that layers the pixel
section containing formations of back-illuminated
structure pixels over the chip affixed with mounted
circuits for signal processing, which is in place of
supporting substrates used for conventional
back-illuminated CMOS image sensors. With this stacked
structure, large-scale circuits can now be mounted
keeping small chip size. Furthermore, as the pixel
section and circuit section are formed as independent
chips, a manufacturing process can be adopted,
enabling the pixel section to be specialized for
higher image quality while the circuit section can be
specialized for higher functionality, thus
simultaneously achieving higher image quality,
superior functionality and a more compact size. In
addition, faster signal processing and lower power
consumption can also be achieved through the use of
leading process for the chip containing the circuits.

As the first step towards the commercialization of its
new CMOS image sensors, Sony has developed a model
with built-in signal processing functionality, an
element that usually requires external embedment.
Samples will be shipped from March, 2012.

The new CMOS models have been also developed with
Sony's "RGBW Coding" function, which contributes to
low noise, high quality image capturing even in low
light condition, and the proprietary "HDR (High
Dynamic Range) Movie" function, which achieves
brilliant color even when taking pictures against
bright light.

The built-in "RGBW Coding" function adds W (White)
pixels to the conventional range of RGB
(Red-Green-Blue) pixels, realizing higher sensitivity
and enabling high-quality shooting with low noise even
in dark indoor or night settings. While the addition
of W (White) pixels improves sensitivity, the image
quality typically degrades. Sony claims that its own
device technology and signal processing realizes
superior sensitivity without hurting image quality.
Furthermore, while the individual pixels of the newly
developed models are extremely minute at 1.12um, the
incorporation of the "RBGW Coding" function has
realized a SN ratio (signal-to-noise ratio) equivalent
to that of a unit pixel size of 1.4um under
conventional methods, which in turn enable the image
sensors to achieve a higher resolution at a more
compact size.

The new models are also able to output signals through
the conventional RGB method, thus there is no need to
change the signal processing adopted in existing
devices.

Typically, when shooting with differing light levels,
such as an indoor setting against a bright outdoor
background, there can easily be blocked up shadows for
dark areas or blown out highlights for bright areas.
Such phenomena are a result of the combination of
low-light and bright-light which have different
optimal exposure conditions in the same shot. Sony's
HDR (High Dynamic Range) Movie function reduces this
by setting two different exposure conditions within a
single screen shooting and conducts the appropriate
signal processing for the captured image information
under each optimal exposure condition. This process
generates an image with a broad dynamic range and
enables shooting of both the background and subject
matter with brilliant colors even in a bright
environment.